The present invention relates to the field of contamination sensitive equipment, such as a tablet dispenser. More particularly, the present invention is directed to a novel conveyor for transporting contamination sensitive material.
In all aspects of the pharmaceutical trade, product safety issues are of paramount importance. From the raw materials to the final container sitting on the druggist""s shelf, the product undergoes countless checks to ensure that what is in the pill bottle has been, among other things, correctly manufactured and properly labelled. Given the nature of a pharmaceutical product, it is critical to ensure that any possible contamination of the product is prevented throughout the manufacturing and packaging process, as product cross-contamination may pose a serious threat to public health and safety.
Accordingly, an important requirement for pharmaceutical production systems is that they be implemented in clean rooms in which the air circulation is carefully controlled and heavily filtered. The expense associated with air handling in these clean rooms is extremely high, and increases with the size of the room. The larger the machines in use by the pharmaceutical production system, the larger the clean room and related costs will be.
Tablet packaging machines are used in the pharmaceutical industry to fill bottles with pharmaceutical tablets or pills, and are one example of equipment that must handle various types of contamination-sensitive material. Traditionally, both the vibratory-type tablet dispenser and the slat-type tablet dispenser have been used within pharmaceutical production systems to fill bottles with tablets. Although functional, both types of machines can be improved on, in particular with respect to the size of the machine, the speed of operation of the machine and the degree of maintenance required in order to prevent possible contamination of the pharmaceutical products being processed by the machine.
In the case of the slat-type tablet dispenser, typically the faster of the two machines, slats of different types are connected in a continuous chain that forms a conveyor for transporting and processing tablets. Each different type of slat performs a different function within the chain of slats, where examples of the different types of slats include test slats, time-wasting slats and slats with cavities for receiving and carrying the tablets The different slats are connected to each other according to a particular order, type and quantity in order to ensure that the tablets are correctly and safely processed. During different tablet packaging operations, a particular chain of slats may be re-used to carry tablets of different chemical compositions that share a similar size and shape, and thus require a similar cavity geometry. In order to prevent cross-product contamination, the slats must be meticulously washed and cleaned before switching from one tablet packaging operation to another. Unfortunately, the washing or a chain of slats may take several hours to complete, reducing the productivity of the tablet packaging machine. Further, oven when the slats have been carefully washed, the possibility of cross-contamination may remain.
The background information provided above clearly indicates that there exists a need in the industry to provide an improved apparatus and method for handling, transporting and packaging contamination sensitive material, such as pharmaceutical tablets.
The present invention provides in one aspect a disposable conveyor for use with an, apparatus handling contamination-sensitive discrete items. The conveyor defines a support surface having at least one cavity, each cavity capable to carry at least one discrete item. The conveyor is adapted to be mounted on the contamination-sensitive apparatus that, in operation, is capable to impart movement to the conveyor for displacing the support surface along a predetermined path. The predetermined path includes an inflection area, at least a section of the conveyor including a continuous sheet of material that possesses sufficient flexibility to bead et this inflection area. When a cavity in the support surface passes over the inflection area during displacement of the support surface along the predetermined path, the cavity releases any discrete items contained therein.
Advantageously, the conveyor as described above is relatively easy to manufacture and, if desired, to maintain, all at a very low cost. Above all, the conveyor is economically disposable. This is particularly beneficial in the pharmaceutical industry where equipment may be required to sequentially handle several different types of pharmaceutical products and any cross-contamination of these pharmaceutical products must be avoided at all costs.
In the present specification, the expression xe2x80x9cconveyorxe2x80x9d encompasses a broad category of apparatuses for moving articles, discrete items and/or materials from place to place.
In a particular, non-limiting example of implementation, a tablet dispenser is operative to fill containers with tablets. The tablet dispenser includes a tablet bin for retaining tablets, a container filling station for directing tablets to containers and a conveyor having cavities. A drive unit imparts movement to the conveyor for displacing the conveyor along a predetermined path. The cavities in the conveyor are filled with tablets as the conveyor moves under the tablet bin, the conveyor transporting tablets in its cavities from the tablet bin to a tablet releasing station at which tablets are released from the cavities to the container filling station.
Specific to the present invention, the conveyor of the tablet dispenser is a disposable, continuous loop (also referred to as a belt) of flexible material, such as plastic. Cavities are formed integrally in the flexible material of the belt, for example through a well-known plastic vacuum forming process. The belt is mounted on first and second belt rollers of the tablet dispenser, and is driven by the drive unit along a continuous loop path defined around the belt rollers. In operation, tablets released from the tablet bin fall into cavities of the belt, which transports these tablets to the tablet releasing station that is implemented by the first belt roller. As the belt moves over the inflection area defined by the first belt roller, any tablets contained in the cavities of the belt fall out of the cavities. A plurality of chutes adjacent the first belt roller implement the container filling station, receiving the tablets released from the cavities of the belt at the tablet releasing station and directing them to containers.
In a specific example, the conveyor includes an identifier that uniquely identifies the conveyor. This identifier may include reference data characterising the conveyor for a particular operation to be performed by the apparatus handling contamination-sensitive discrete items, where this reference data may be used to validate the conveyor prior to its use by the apparatus. The identifier may also include position data for uniquely identifying the conveyor cavities, such that monitoring of the cavities and their contents would be possible. The identifier may be implemented as one or more machine-readable bar codes, printed on or etched into the material of the conveyor. Alternatively, the identifier could be implemented as a machine-readable magnetic tag or strip bonded to the conveyor. In yet another alternative, the identifier could be implemented by operator-readable data printed on the conveyor, among other possible implementations.
In another broad aspect, the invention provides an apparatus for transporting discrete items. The apparatus includes a holding station, a disposable conveyor and a drive unit. The holding station retains a plurality of discrete items, and is capable to release these discrete items to the conveyor. The conveyor includes a plurality of cavities, each cavity capable to carry at least one discrete item, while the drive unit is operative to impart movement to the conveyor for displacing the conveyor along a predetermined path. As the conveyor moves beneath the holding station, its cavities arc filled with discrete items, the conveyor being operative to transport discrete items in its cavities along the predetermined path.
According to yet another broad aspect, the present invention provides a method for transporting discrete items in a machine performing production runs with different types of contamination-sensitive discrete items.